It's a weird site - I put in different zip codes and get different mixes of restaurants. For example, if I put in a zip code for about the center of Kansas City, I get shown a many options extending 25 miles south but zero options going north, as if the Missouri River is a magic McRib Line.

Then I throw in a zip code that is barely north of the river, and all of those McDonald's show up.

So I *think* it's everywhere, but I don't actually care enough to go find out.